Laudator Temporis Acti

Jonathan Swift (1667-1745), Gulliver's Travels IV.v:

Difference in Opinions hath cost many Millions of Lives: For Instance, whether Flesh be Bread, or Bread be Flesh: Whether the Juice of a certain Berry be Blood or Wine: Whether Whistling be a Vice or a Virtue: Whether it be better to kiss a Post, or throw it into the Fire: What is the best colour for a Coat, whether Black, White, Red, or Grey; and whether it should be long or short, narrow or wide, dirty or clean; with many more. Neither are any Wars so furious and bloody, or of so long Continuance, as those occasioned by Difference in Opinion, especially if it be in things indifferent.

Irvin Ehrenpreis, Swift: The Man, His Works, and the Age, Vol. III: Dean Swift (Cambridge: Harvard University Press, 1983), pp. 461-462:

The expression, 'difference in opinions', is a euphemism for religious differences. The controversy over flesh and bread is of course over the doctrine of transubstantiation, which divides Protestants from Roman Catholics. So also is the controversy over blood and wine. Whistling is a reference to the use of instrumental music in church, which the Church of England favoured and certain Dissenting sects opposed. The post is the cross, and the controversy here is over its veneration or its destruction as a misleading symbol.